1. Field of the Invention
The present invention relates to a side-collision airbag apparatus for restraining an occupant at the time of a side collision of a vehicle, such as an automobile.
2. Description of the Related Art
There are known side-collision airbag apparatuses configured to inflate a side-collision airbag toward the side portion of an occupant via an inflator and restrain the body of the occupant at the time of a vehicle side collision, lateral overturn, or the like. Examples of side-collision airbags include airbags divided into a pelvis chamber and chest chamber. The injected gas from the inflator is appropriately distributed and introduced into each chamber, causing the airbag to deploy in an inflated state appropriate for each chamber.
With such a side-collision airbag apparatus, there is known a structure wherein the inflator is assembled to the side-collision airbag via an inflator holder (see JP, A, 2009-73232, and JP, A, 2008-18925). According to this prior art, the inflator holder comprises a holding portion that holds the inflator, and a diffuser portion that distributes and supplies gas from the inflator to each chamber of the side-collision airbag. The diffuser portion comprises a diffuser tube that has a cross-section that is circular in shape, and comprises a contraction opening positioned on the tip end side, and another opening positioned on the base end side through which the inflator is inserted. In addition, a gas distribution chamber is formed on the inside of the diffuser tube. The inflator comprises an inflator main body portion having a substantially cylindrical shape, and an injecting portion provided so as to protrude from the tip end of the inflator main body portion.
In the above-described prior art, the tip end side of the inflator main body portion is inserted into the gas distribution chamber inside the diffuser tube, with the inflator held by the holding portion of the inflator holder. At this time, a gap channel is formed between the outer peripheral surface of the inflator main body portion and inner peripheral surface of the diffuser tube. When the gas is injected from the injecting portion of the inflator, the gas in the gas distribution chamber is distributed from the gas distribution chamber to a front-end direction gas flow that flows straight along the injection direction via the contraction opening, and a base-end direction gas flow that is reversed to the opposite direction in the gas distribution chamber and flows toward the base-end direction of the inflator via the gap channel.